人类活动对大亚湾海域鱼类群落多样性及其演替的影响

根据2015—2016年间对大亚湾海域进行的4个航次底拖网调查数据,分析了大亚湾鱼类群落的种类组成和多样性特征。结果表明,调查共采集到鱼类131种,隶属14目、53科、84属。其中以鲈形目(Perciformes)占绝对优势(54.20%),其次是鳗鲡目(Agunilliformes)和鲽形目(Pleuronectiformes),均占9.92%。种类数具明显季节变化,以夏季最高,69种;春季最低,32种。鱼类群落优势种组成主要以二长棘犁齿鲷(Evynnis cardinalis)、李氏(Callionymus richardsoni)、斑(Clupanodon punctatus)、竹荚鱼(Trachurus japonicus)、黄鳍马面鲀(Thamnaconus hypargyreus)、短吻鲾(Leiognathus brevirostris)和细条天竺鲷(Apogon lineatus)等小型鱼类为主。多样性分析显示,鱼类物种多样性存在明显的季节差异和空间差异。季节变化上,多样性指数(H')季节变化范围为1.516~1.998,以冬季最高,秋季最低;均匀度指数(J')季节变化范围为0.494~0.869,以冬季最高,夏季最低;丰富度指数(D')季节变化范围为2.230~3.777,以夏季最高,秋季最低。典范对应分析表明,温度、盐度和水深是影响大亚湾海域鱼类群落结构的主要环境因子。空间分布上,海湾中部海域鱼类多样性水平高于沿岸海域。与历史资料相比,由于人类活动对大亚湾生态系统的干扰,鱼类群落结构发生了较大变化,优势种组成更替明显,多样性水平降低,鱼类群落结构趋向简单化。

The effects of anthropogenic activities on the diversity and succession of fish community in Daya Bay

The aim for the present study was to analyze data from four otter trawl surveys (conducted between 2015 and 2016) in order to investigate variation in the composition and diversity of fish species in Daya Bay, South China. The data included 131 species, which belonged to 84 genera, 53 families, and 14 orders. Species of the Perciformes were the most predominant, accounting for 54.20%, followed by those of the Agunilliformes and Pleuronectiformes, each accounting for 9.92%. Seasonal (temporal) variations of species number were obvious, with the greatest number of species observed during summer (n=69) and the lowest observed during spring (n=32). The predominant fish species included Evynnis cardinalis, Callionymus richardsoni, Clupanodon punctatus, Trachurus japonicus, Thamnaconus hypargyreus, Leiognathus brevirostris and Apogon lineatus. Diversity analysis revealed significant seasonal and spatial differences in fish species diversity. The diversity index (H'') ranged from 1.516 to 1.998, with the greatest value observed during winter and the lowest during autumn, whereas the evenness index (J'') ranged from 0.494 to 0.869, with the greatest value observed during winter and the lowest during summer, and the richness index (D'') ranged from 2.230 to 3.777, with the greatest observed during summer and the lowest during autumn. Model analysis indicated that temperature, salinity, and water depth are the main environmental factors affecting the structure of the fish community in Daya Bay. In terms of spatial distribution, fish diversity was greater in the middle of the bay than in coastal waters. Compared with historical data, the fish community structure has changed significantly, as a result of disturbance from anthropogenic activities, including obvious changes in the composition of dominant species and reduced diversity, suggesting the simplification of fish species appeared in this bay.